首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   177篇
  免费   22篇
儿科学   4篇
妇产科学   1篇
基础医学   43篇
口腔科学   2篇
临床医学   19篇
内科学   57篇
皮肤病学   3篇
神经病学   19篇
特种医学   4篇
外科学   14篇
预防医学   14篇
眼科学   1篇
药学   13篇
肿瘤学   5篇
  2022年   1篇
  2020年   2篇
  2019年   1篇
  2018年   3篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   2篇
  2012年   10篇
  2011年   10篇
  2010年   1篇
  2009年   6篇
  2008年   9篇
  2007年   13篇
  2006年   9篇
  2005年   7篇
  2004年   9篇
  2003年   6篇
  2002年   12篇
  2001年   7篇
  2000年   15篇
  1999年   10篇
  1998年   2篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1994年   2篇
  1993年   1篇
  1992年   5篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1984年   3篇
  1982年   2篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1964年   1篇
  1954年   1篇
排序方式: 共有199条查询结果,搜索用时 15 毫秒
1.
We analyzed the variations observed in the plasma levels of both alpha-macroglobulins (AM) and serum amyloid P (SAP) in mice from three different inbred strains (C3H, Balb/C and C57black/6) acutely infected withTrypanosoma cruzi. SAP levels increased in C57black/6 and Balb/C mice but not C3H mice. AM levels increased in all C3H mice but not in C57black/6 mice and rose slightly in only 43% of the Balb/C mice. AM and SAP levels are differently modulated in patterns that may be strain-determined.  相似文献   
2.
Lifestyle including eating habits, physical training, smoking, drinking alcoholic beverages etc. can to a certain extent maintain or spoil our health. The physiological mechanisms of haemostasis and of lipoprotein metabolism play a role in acute cardiovascular diseases but also in a great number of chronic diseases in which vascular pathology is prominent. Impaired fibrinolysis and increased lipid levels are often incriminated in vascular disease. Lifestyle can modify fibrinolysis as well as lipid levels. Physical training, moderate eating habits, no smoking, moderate alcohol intake will be a beneficial influence on both fibrinolysis and lipid levels. The possibility that longterm pharmacological intervention may adversely affect fibrinolysis and lipid levels should always be considered.  相似文献   
3.
The contribution of mutations in the amyloid precursor protein (APP) gene known as Flemish (APP/A692G) and Dutch (APP/E693Q) to the pathogenesis of Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis of the Dutch type, respectively, was studied in transgenic mice that overexpress the mutant APP in brain. These transgenic mice showed the same early behavioral disturbances and defects and increased premature death as the APP/London (APP V717I), APP/Swedish (K670N, M671L), and other APP transgenic mice described previously. Pathological changes included intense glial reaction, extensive microspongiosis in the white matter, and apoptotic neurons in select areas of the brain, while amyloid deposits were absent, even in mice over 18 months of age. This contrasts with extensive amyloid deposition in APP/London transgenic mice and less pronounced amyloid deposition in APP/Swedish transgenic mice generated identically. It demonstrated, however, that the behavioral deficiencies and the pathological changes in brain resulting from an impaired neuronal function are caused directly by APP or its proteolytic derivative(s). These accelerate or impinge on the normal process of aging and amyloid deposits per se are not essential for this phenotype.  相似文献   
4.
Long‐term survival after esophagectomy is improving, and hence, quality of life (QOL) of these patients has become a priority. There has been extensive debate regarding the optimal site of surgical anastomosis (cervical or intrathoracic). We aimed to evaluate the impact of anastomotic site on long‐term QOL postesophagectomy. Quality of life questionnaires (European Organisation for Research and Treatment of Cancer [EORTC] C‐30 and OG‐25) were sent to patients surviving over 3 years following esophagectomy. The data were analyzed by site of esophagogastric anastomosis: intrathoracic or cervical. EORTC C‐30 data were compared against the reference population data. Of the patients, 62 responded (82%) with a median time postsurgery of 6.1 years (range 3–12 years). Patient demographics were comparable. There was no significant difference between cervical or intrathoracic anastomosis groups for functional or symptom scores, focusing on dysphagia (cervical = 8.8 vs. intrathoracic = 17.6, P = 0.24), odynophagia (cervical = 13.4 vs. intrathoracic = 16.1, P = 0.68) and swallowing problems (cervical = 8.1 vs. intrathoracic = 13.4, P = 0.32). There was no difference in overall health score between groups (cervical = 70.5 vs. intrathoracic = 71.6, P = 0.46). Overall general health score was comparable with the reference population (esophagectomy group P = 70.9 ± 22.1 vs. reference population = 71.2 ± 22.4, P = 0.93). There is no difference in long‐term QOL after esophagectomy between patients with a cervical or intrathoracic anastomosis. Scores compare favorably with EORTC reference data. Survival after esophagectomy is associated with recovery of QOL in the long term, regardless of site of anastomosis and despite worse gastrointestinal‐related symptoms.  相似文献   
5.
Five coding polymorphisms in de LRP1 gene, i.e. A217V, A775P, D2080N, D2632E and G4379S were discovered by sequencing its 89 exons in three test-groups of 22 healthy individuals, 29 Alzheimer patients and 18 individuals with different clinical and molecularly uncharacterized lipid metabolism problems. No genetic defect was evident in the LRP1 gene of any of the Alzheimer's disease (AD) patients, further excluding LRP1 as a major genetic problem in AD. Lipoprotein receptor related protein (LRP) A217V (exon 6) was clearly present in all groups as a polymorphism, while D2632E was observed only once in a healthy volunteer. On the other hand, LRP1 alleles A775P, D2080N, and G4379 were encountered only in patients with FH or with undefined problems of lipid metabolism. This finding forced one to also analyze the LDL receptor (LDLR) gene, for which a method was devised to sequence the entire region comprising LDLR exons 2-18. The resulting sequence contig of 33567 nucleotides yielded finally an exact physical map that corrects published and listed LDLR gene maps in many positions. In addition, next to known mutations in LDLR that cause FH, four novel LDLR defects were defined, i.e. del e7-10, exon 9 mutation N407T, a 20 bp insertion in exon 4, and a double mutation C292W/K290R in exon 6. No evidence for pathology connected to the LRP1 'mutations' was obtained by subsequent screening for the five LRP1 variants in larger groups of 110 FH patients and 118 patients with molecularly undefined, clinical problems of cholesterol and/or lipid metabolism. In three individuals with a mutant LDLR gene a variant LRP1 allele was also present, but without direct, obvious clinical compound effects, indicating that the variant LRP1 alleles must, for the present, be considered polymorphisms.  相似文献   
6.
Plasma values of C reactive protein, alpha 1 proteinase inhibitor, alpha 2 macroglobulin, and complexed alpha 2 macroglobulin have been determined in serial samples from 27 patients with acute pancreatitis. Complexed alpha 2 macroglobulin was measured by a novel enzyme linked immunosorbent assay with a monoclonal antibody specific for the complexed form. Patients with severe illness had lower concentrations of total alpha 2 macroglobulin and higher concentrations of complexed alpha 2 macroglobulin than those with mild illness, and in the majority of severe attacks the abnormal amounts of complexed alpha 2 macroglobulin were present throughout the eight days of the study. The proportion of total alpha 2 macroglobulin in the uncomplexed form, however, was generally greater than 90%, and in 26% of the mild cases completely normal concentrations of uncomplexed alpha 2 macroglobulin (greater than 99% of total) were found throughout the eight days of the study. This suggests that exhaustion of alpha 2 macroglobulin in plasma is unlikely to be a major factor in the pathogenesis of acute pancreatitis.  相似文献   
7.
OBJECTIVE: In hypertriglyceridemic patients, hypertension occurs frequently and may be associated with hyperinsulinemia and elevated plasma levels of free fatty acids (FFA). Besides the lipid-lowering effects, fibrates have been shown to reduce blood pressure in hypertensive patients. The present study was undertaken to investigate the effects of bezafibrate on hemodynamics in relation to insulin, FFA, sympathetic activity, renal sodium absorption, cyclic-GMP (cGMP) and endothelin-1 in hypertriglyceridemic patients. SUBJECTS AND METHODS: Hypertriglyceridemic patients (17) were randomized to receive in a double-blind placebo-controlled study bezafibrate or placebo for 6 weeks. At the end of both treatment periods, blood pressure and heart rate were measured automatically. Plasma insulin, FFA, aldosterone, catecholamines, cGMP, endothelin-1 levels and 24 h urine catecholamines and sodium excretion were assessed. RESULTS: Bezafibrate therapy decreased serum triglycerides (-65%, P < 0.001) and hemodynamic parameters: heart rate decreased from 69 to 66/min (P = 0.009), systolic blood pressure from 137 to 132 mmHg (P = 0.01), diastolic blood pressure from 81 to 79 mmHg (P = 0.07) and mean blood pressure from 102 to 99 mmHg (P = 0.06). Bezafibrate therapy reduced FFA and insulin (-55 and -57% respectively, both P < 0.001), while sympathetic activity and renal sodium absorption were not affected. cGMP increased (+17%, P = 0.008), whereas endothelin-1 levels tended to decrease upon bezafibrate therapy (-10%, P = 0.077) CONCLUSION: Bezafibrate reduces heart rate, blood pressure, insulin and FFA in hypertriglyceridemic patients. The hemodynamic effects cannot be attributed to changes in sympathetic activity or renal sodium absorption. Instead, based on the increase in plasma cGMP levels, the bezafibrate-induced hemodynamic effects are most likely to be caused by bezafibrate-induced improvement of endothelial function.  相似文献   
8.
9.
The deposition of the amyloid beta-protein (Abeta) is a hallmark of Alzheimer's disease (AD). One reason for Abeta-accumulation and deposition in the brain may be an altered drainage along perivascular channels. Extracellular fluid is drained from the brain towards the cervical lymph nodes via perivascular channels. The perivascular space around cerebral arteries is the morphological correlative of these drainage channels. Here, we show that Abeta is immunohistochemically detectable within the perivascular space of 25 months old wild-type and amyloid precursor protein (APP)-transgenic mice harboring the Swedish double mutation driven by a neuron specific promoter. Only small amounts of Abeta can be detected immunohistochemically in the perivascular space of wild-type mice. Cerebrovascular and parenchymal Abeta-deposits were absent. In APP-transgenic mice, large amounts of Abeta were found in the perivascular drainage channels accompanied with cerebrovascular and parenchymal Abeta-deposition. The apolipoprotein E (apoE) immunostaining within the perivascular channels did not vary between wild-type and APP-transgenic mice. Almost 100% of the area that represents the perivascular space was stained with an antibody directed against apoE. Here, Abeta co-localized with apoE indicating an involvement of apoE in the perivascular clearance of Abeta. Fibrillar congophilic amyloid was not seen in wild-type mice. In APP-transgenic animals, congophilic fibrillar amyloid material was seen in the wall of cerebral blood vessels but not in the perivascular space. In conclusion, our results suggest that non-fibrillar forms of Abeta are drained along perivascular channels and that apoE is presumably involved in this clearance mechanism. Overloading such a clearance mechanism in APP-transgenic mice appears to result in insufficient Abeta-clearance, increased Abeta-levels in the brain and the perivascular drainage channels, and finally in Abeta-deposition. In so doing, our results strengthen the hypothesis that an alteration of perivascular drainage supports Abeta-deposition and the development of AD.  相似文献   
10.
Few studies have presented a thorough analysis of young adults with symptoms of arterial occlusive disease. To learn more about the possible risk factors of vascular disease playing a role in these young patients, we have reviewed all patients of 45 years of age and younger with symptoms of arterial occlusive disease who had been referred to our department between 1978 and 1987. Thirty-seven patients (28 males and 9 females) were included in the study. The mean age at which the first symptoms occurred was 34 years. Most patients presented with chronic arterial obliterations of the lower extremities (31/37, 84%). In addition, 4 patients showed signs of ischaemic heart disease. A strongly positive family history of arteriosclerosis was obtained from 13 patients (35%). Hypertension was present in 7 patients (19%), diabetes in three (8%) and nicotine abuse was found in 27 patients (73%). Fifty-four percent of the patients (20/37) had undergone vascular reconstructive surgery, 19% (7/37) underwent transluminal dilatation, and 3 had had subsequent treatment of newly developed lesions. For this study, all patients were recalled to the outpatient clinic. A complete case history was taken followed by a physical examination and ECG. Laboratory examinations were performed to analyse parameters of: (a) coagulation; (b) fibrinolysis; (c) fat- and (d) methionine metabolism. Clear-cut laboratory abnormalities were found in 33 patients (33/37, 89%). Coagulation parameters were abnormal in 11 patients (30%) (protein S deficiency: 3 pts). Fibrinolysis was impaired in 15 patients (40%).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号